What Causes Continuous Bleeding After Intercourse Even After Using Mercilon?

Good day Dr... I was on Minesse for 9 months.,.. the first 4 months I started with my period a week before it was due... then I started with spotting.. I phoned my gyne went for a papsmear got normal results... Then my husband and I had intercourse and the next day I started bleeding again for 2 weeks.. phoned my gyne she prescribed Mercilon which I started.. I have been on Mercilon for 2 weeks now and there is still bleeding... what can this be??